Bhleu: ‘To Blow or to swell’ from Proto-Indo-European
Life flows and leaves, wind, clouds, fire and storms bhleu/blow. From this ancient word comes many other beautiful nature words we know and love today, such as:
Blót, an ancient Norse rite of blood sacrifice, also derived from the word bhleu
For the Teutons ( an ancient Germanic tribe) a blessing originally meant to consecrate an altar in the blood of a human or animal sacrifice.
Later on in Latin, the sound softened and the bh turned into an f sound.
Fluere in Latin means to flow
From this change we get yet more beautiful words such as:
Mellifluous: flowing sweetly
Superfluous: Which originally meant flowing over but has come to mean wasteful or pointless now.
Confluence: The flowing together of two things.
Affluent: The flowing of money.
An Etymological Dictionary of the English Language By Walter W. Skeat (1910)
A Concise Dictionary of Middle English From A.D. 1150 To 1580 by A. L. Mayhew and Walter W. Skeat (1888)